New window technologies are reducing heat transfer through the glazed areas of windows.sLow-emissivity (low-E) coatings reduce radiative heat transfer and low-conductivity gas fillss(which replace the air between glazing layers) reduce conductive heat transfer. Given thesesadvances in insulating glass technology, researchers and manufacturers are now beginning tosfocus their attention on reducing heat transfer through window edges. Old edge designs aresnow under scrutiny and new designs are being proposed.

This paper explores window material and design parameters which influence heat transfer usingstwo-dimensional heat-transfer modeling with an advanced finite-element computer codes(ANSYS). A comprehensive set of correlations, based on ANSYS parametrics, is thensdeveloped. These correlations are compared, whenever possible, to experimental results and willsbe incorporated into future versions of the WINDOW program. Glazing edge designs analyzedsinclude both double-glazed and triple-glazed options with aluminum, steel, wood, fiberglass,sbutyl, and insulated spacers. Single and double seal design are also analyzed.